Help with Python COM Type Mismatch

[Markus Wankus]

On 13 Dec 2002 20:55:38 GMT, Uwe Schmitt <uwe.schmitt at procoders.net> wrote:
> Markus Wankus <markus_wankus at hotmail.com> wrote:
> > Well, I received a lot of help from Mark on this one, and finally have 
> > figured things out.  If anyone is interested, let me know and I will 
> > share my experiences.
> 
> Yes, I'm interested.
> 
> Greetings, Uwe.
> 
>
Well, I will try to sum up.  I was dealing with an API  (Solidworks) which apparently is not "normal" and is similar to Lotus 
Notes in it's stupidness.  It has a well-defined type library but seemed to know nothing about it when you tried to use it.  
I was using early bindings with gencache, but it didn't seem to be having any effect.  So, what I was doing was this:

#<start of Python code>
from win32com.client import Dispatch, gencache, constants, pythoncom
sldmod = gencache.EnsureModule('{83A33D31-27C5-11CE-BFD4-00400513BB57}', 0, 10, 0)

# Attach to Solidworks
sldwrks = Dispatch("SldWorks.Application")
print repr(sldwrks)

part = sldwrks.ActiveDoc
a, b = sldwrks.OpenDocSilent(r'E:\SolidData\Detail Drawings\C00-000421.SLDDRW', swDocDRAWING)
#<end of Python code>

This code attaches to Solidworks, gets the Active document open, then it
fails - telling me the last argument to OpenDocSilent() is not optional.  There were also other various methods giving me 
weird errors about Unicode until I tried specifying the methods without the brackets - then it would work.

The key here is the "print repr(sldwrks)" above produced:

<COMObject SldWorks.Application>

Indicating early binding was not happening.  It was suggested I try the following instead:

#<start of Python code>
from win32com.client import Dispatch, gencache, constants, pythoncom
sldmod = gencache.EnsureModule('{83A33D31-27C5-11CE-BFD4-00400513BB57}', 0, 10, 0)

# Attach to Solidworks
sldwrks = Dispatch("SldWorks.Application")
sldwrks = sldmod.ISldWorks(sldwrks)

part = sldmod.IModelDoc(sldwrks.ActiveDoc)

(...same code as before after this point)

This worked.  Notice that for every object I create, I pass what *should* work, to the constructor of the interface - and I 
magically get back a proper object.  

Anyway, I still don't know much about this whole COM thing, but at least this part of it works now!

Regards,
--
Markus.